JPH0330101A - Magneto-optical disk device - Google Patents

Abstract

PURPOSE:To make an external magnetic field applied to a medium stable near a recording layer while making the size small and the profile of the device thin by providing an external magnetic field generating means used for recording or erasure while being integrated in a cartridge case support means. CONSTITUTION:An external magnetic field generating means is integrated to a cartridge case support means 20. The magnetic flux 40 generated from two magnets 21 in recording or erasing is concentrated in the vicinity of a light spot focused onto a medium 17. The switching in the direction of the magnetic field at recording and erasure is implemented by inverting the magnets 21 with a magnetic field inversion circuit 15. Moreover, since the medium 17 and the holder 20 rise and fall at the place in which vibration is large, the external magnetic field applied to the medium 17 in recording or erasing is always stable near the recording layer. Thus, efficient recording or erasure is applied without excess external magnetic field. Thus, the device is made small and the profile is made thin and the magnetic field is made stable near the recording layer of the medium 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical disk device that magneto-optically records and reproduces information.

[Prior Art] In conventional magneto-optical disk drives, the external magnetic field generating means generally consists of an electromagnet placed near the optical head. However, some of them are 63-129202
There was also a structure in which an electromagnet was built into the cartridge case that housed the magneto-optical recording medium, as shown in the above publication.

Further, the cartridge case holding means in a magneto-optical disk device is used when the cartridge case is inserted into the device, and usually no external magnetic field generating means is attached.

[Problems and objects to be solved by the invention] However, when using the external magnetic field generating means of the conventional magneto-optical disk device, there is a problem that the space occupied by the magnetic field generating coil cannot be ignored and the device becomes thicker than necessary. there were.

Furthermore, when a magneto-optical disk drive is used in a place with large vibrations, for example, the vibration causes the coil and the medium to vibrate up and down, causing their relative positions to fluctuate, resulting in the problem that the magnetic field tends to fluctuate near the recording layer of the medium. Ta. In this case, the solution was to run a large current through the coil to compensate for the variation in the magnetic field, but this was quite inefficient as the coil generated more heat and the device consumed more current.

The present invention is intended to solve these problems, and its purpose is to stabilize the external magnetic field applied to the medium near the recording layer while making the optical disc device smaller and thinner. .

[Means for Solving the Problems] A magneto-optical disk device of the present invention includes an optical head that irradiates a laser beam onto the surface of a magneto-optical recording medium, a frame that supports the optical head, and a frame that supports the optical head and the magneto-optical recording medium. an access mechanism that scans and drives a medium in a seek direction; a spindle motor that attaches and rotates a cartridge case containing the magneto-optical recording medium; a cartridge case holding means that engages with and operates the frame; In a magneto-optical disk device having at least a means for detecting reflected light or transmitted light from a magneto-optical recording medium and reproducing information, an external magnetic field generator built in the cartridge case holding means and used for recording or erasing. It is characterized by comprising means.

[Example] The following is about the present invention. This will be explained in detail based on examples.

FIG. 1 is a schematic side view showing an embodiment of a magneto-optical disk device of the present invention. Here, reference numeral 1 denotes an optical head, which includes a laser light source 2, an objective lens 6 that focuses the light from the laser light source onto the magneto-optical recording medium, and an optical system in the seek direction and direction with respect to the magneto-optical recording medium, respectively. A tracking actuator 7 and a focus actuator 8 are included for making minute movements in the optical axis direction.

Next, the functions of each part during recording, playback, or erasing will be explained. A laser beam generated by a light source 2 by a laser drive circuit 10 passes through a collimating lens 3, a polarizing beam splitter 4, and a quarter-wave plate 5, and then is focused as a light spot onto a magneto-optical recording medium 17 by an objective lens. The magneto-optical recording medium is housed in a cartridge case l8, and is mounted on a spindle motor 16 via a metal hub portion 19 and rotated. Information is recorded and erased by irradiating the medium with the light spot while applying an external magnetic field to the medium. To reproduce recorded information, the light reflected from the medium passes through the polarized beam splitter again, is detected by the photodetector 9, and is processed by the reproduction signal processing circuit 14 as reproduction data.

Focus control circuit 13 controls the focus shift of the light spot.
This is done by moving the focus actuator. Similarly, tracking deviation is controlled by the tracking control circuit 12.
This is done by driving the tracking actuator. Rough access to the track is provided by the optical head drive motor 11.
This is done by moving the optical head in the seek direction.

Unlike magnetic disk devices and the like, magneto-optical disk devices use electromagnetic coils to apply an external magnetic field of a predetermined magnitude to the medium during recording or erasing.

In the conventional magneto-optical disk device shown in FIG. 4, a coil drive circuit 52 and a coil 51 perform this function. However, in the example shown in Figure 4. Since the coil is located opposite the objective lens with the medium in between, and the coil is thick, there is a problem in that the magneto-optical disk device becomes thicker than necessary.

Furthermore, when the device is used in a place with large vibrations, the vertical vibration of the medium also increases and the relative position between the coil and the medium changes, causing the magnetic field to fluctuate near the recording layer, making efficient recording or erasing difficult. There was also.

Therefore, in the present invention, as shown in FIGS. 1 and 2, an external magnetic field generating means is incorporated into the cartridge case holding means 20, that is, the holder. As shown in FIG. 2, this external magnetic field generating means has a magnet 21 placed in a holder that operates by engaging with a frame 30. This magnet is made of small and strong samarium cobalt, has a thickness of about several mm, and is long enough to cover the seek scanning area of the optical head.

Also, as shown in Figure 2, two magnets are incorporated so that they can rotate within the holder.

Next, a description will be given of how an external magnetic field is applied to the medium. Third
As shown in the figure, in the embodiment of the present invention, the magnetic flux 40 generated by the two magnets 21 during recording or erasing is concentrated near the optical spot focused on the medium. Also, how to switch the magnetic field direction during recording and erasing. Magnetic field reversal circuit 1 in Fig. 1
5, the magnet 21 is reversed.

Furthermore, when a magneto-optical disk device is used in a place with large vibrations, unlike conventional systems, the medium and holder move up and down as one, so the external magnetic field applied to the medium during recording or erasing is near the recording layer. is always stable. Therefore, efficient recording or erasing can be performed without applying an excessive external magnetic field as in the conventional case.

The magnet used in the magneto-optical disk device of the present invention is not limited to the samarium cobalt used in the embodiment of the present invention, but any magnet may be used as long as it has good machining accuracy, is small, and is strong.

Furthermore, although this embodiment describes the case where the reflected light from the magneto-optical recording medium is detected and reproduced, the present invention can also be applied to a method of reproducing information using transmitted light from the medium, similar to this embodiment. The effect of this can be obtained.

[Effects of the Invention] As described above, according to the present invention, since the external magnetic field generating means is built into the cartridge case holding means and attached, the magneto-optical disk device can be made smaller and thinner. Furthermore, even if the medium has a large vertical vibration, the medium and the cartridge case holding means move up and down as one, so the magnetic field remains stable near the recording layer of the medium. Therefore, efficient recording or erasing can always be performed without applying an excessive magnetic field to the medium.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an embodiment of a magneto-optical disk device of the present invention, FIG. 2 is a schematic front view showing an embodiment of the present invention,
FIG. 3 is a diagram for explaining the operation of the external magnetic field generating means in the embodiment of the present invention, and FIG. 4 is a schematic side view of a conventional magneto-optical disk device. ...Optical head, laser light source, collimating lens, polarizing beam splitter, quarter wavelength plate, objective lens, tracking actuator, focus actuator, photodetector, laser drive circuit, optical head drive motor 20, tracking Control circuit Focus control circuit Playback signal processing circuit Magnetic field reversal circuit Spindle motor Magneto-optical recording medium Power-tridge case Metal hub cartridge case Holding means Magnet frame Magnetic flux coil Coil drive circuit Fig. 3

Claims (1)

[Claims] an optical head that irradiates a laser beam onto a surface of a magneto-optical recording medium, a frame that supports the optical head, an access mechanism that drives the optical head to scan in a seek direction with respect to the magneto-optical recording medium, and the magneto-optical recording medium. A spindle motor that attaches and rotates a cartridge case containing a medium, a cartridge case holding means that engages with the frame and operates, and reproduces information by detecting reflected light or transmitted light from the magneto-optical recording medium. What is claimed is: 1. A magneto-optical disk device comprising at least a means for recording or erasing data, said magneto-optical disk device comprising external magnetic field generating means built into said cartridge case holding means and used for recording or erasing.